In a news conference this afternoon, Republican California gubernatorial candidate Meg Whitman denied allegations that she knowingly employed an illegal immigrant as a housekeeper, calling the accusations "a baseless smear attack," and adding that "there is very clear evidence that this is Brown-motivated," referring to her Democratic opponent, Jerry Brown.

"First of all, make no mistake: these allegations are completely untrue," Whitman said.

Whitman has come under fire recently after Nicky Diaz Santillan, a former housekeeper, made allegationsthat the billionaire was aware her employee was an undocumented immigrant, and that Whitman had received a 2003 letter from the U.S. Social Security Administration questioning the legitimacy of her housekeeper's citizenship.

Gloria Allred, Diaz Santillan's lawyer, held a news conference later in the afternoon where she unveiledwhat she claimed was that letter, claiming it as proof that Whitman had been "exposed as a liar and a hypocrite."

"I don't know who's paying Gloria Allred," Whitman said, but asserted her belief that the accusations against her were "absolutely linked to the Brown campaign."

"I don't know what was Nicky's decision," Whitman continued. "Did someone come to her house and say, 'We know you're here illegally and were going to expose you unless you do this with Gloria Allred'? I think you all should ask the question of exactly how this occurred... I think that Nicky had a gun to her head."

Whitman denied allegations that she had received any letter from the U.S. Social Security Administration, and added that that if one existed it "somehow it ended up in Jerry Brown's hands or in Gloria Allred's hands."

Whitman also noted the possibility that her former housekeeper could have intercepted the letter.

"It pains me to say that," said Whitman, who emphasized several times throughout the course of the press conference that she had considered Diaz Santillan like a member of her extended family. But she added that if Diaz Santillan had been made aware that her citizenship status was under investigation, "she might have been on the lookout for that letter."

When questioned about Diaz Santillan's claims that Whitman had treated her cruelly during her tenure in the family's home, the former eBay CEO said that such accusations were "completely untrue" and that outside influences were at play.

"Those weren't Nicky's words," Whitman said of the remarks her former employee delivered on Wednesday. "She is being used by cynical people with a selfish agenda... I think she's been manipulated by a very sophisticated attorney who has done this for a living over the last 20 years... I think Jerry Brown should be ashamed of what his allies have tried to do here."

"We had a very good relationship with Nicky," Whitman continued. "Her children came over to our house... Nicky and her boys often played soccer in our back yard... Her little boys used to come over and play with our mini schnauzer."

When asked why, then, Whitman hadn't helped Diaz Santillan gain citizenship upon her admission that she was in the country illegally, Whitman said she "had lied to us for nine years."

Whitman, the billionaire former CEO of eBay who has so far spent more than $100 million of her own money on the campaign, is currently locked in a dead heat with Democrat Jerry Brown in the California Governor's race.

Diaz Santillan worked for Whitman and her husband for nine years, but was fired in 2009 when she approached Whitman about her immigration status and asked for help becoming a U.S. citizen.

Lucy Madison is a political reporter for CBSNews.com. You can read more of her posts here. Follow Hotsheet on Facebook and Twitter.